1. Field of the Invention
The present invention relates to novel polycarbonate resins, a process for production of said resins, and compositions containing said resins. More particularly, the present invention is concerned with novel polycarbonate resins which are excellent in flame retardance, impact resistance, fluidity or moldability, and further in transparency, a process for efficiently producing such polycarbonate resins, and also to compositions containing such polycarbonate resins and glass fibers as major components.
2. Description of the Related Art
As flame retardant polycarbonate resins, polycarbonate having a halogen-substituted phenoxy group (e.g., a pentabromophenoxy group, a tetrachlorophenoxy group, and a tribromophenoxy group) as an end group at the terminal thereof (Japanese Patent Publication No. 40715/1971), a copolymer of tetrahalogenobisphenolsulfone and bisphenol A (BPA) (Japanese Patent Application Laid-Open No. 123294/1976), polycarbonate having an aromatic monosulfonyl group at the terminal thereof (Japanese Patent Application Laid-Open No. 21497/1979), a copolymer of tetrabromobisphenol A and BPA (Japanese Patent Application Laid-Open No. 155233/1982), polycarbonate having a sulfonic acid salt end group (PCT Japanese Patent Application Laid-Open No. 501212/1985), and so forth are known.
These polycarbonate resins, however, are not sufficiently satisfactory in impact resistance, fluidity or moldability and transparency although they are excellent in flame retardance.
In order to improve the impact resistance of polycarbonate resins which are good in flame retardance and transparency although poor in impact resistance, polycarbonate having a thiodiphenoxy group has been developed. For example, polycarbonate produced from thiodiphenol (TDP), halogenated bisphenol and bisphenol A (BPA) (Japanese Patent Application Laid-Open No. 140597/1977), a mixture of polycarbonate produced from TDP and BPA and halogen-containing polycarbonate or halogen-containing compounds (Japanese Patent Application Laid-Open No. 50065/1979), polycarbonate having a tetrabromothiodiphenoxy group (Japanese Patent Application Laid-Open No. 99226/1981), and so forth are known.
However, these polycarbonate resins still have disadvantages in that fluidity is poor and thus they are difficult to mold, although they are excellent in flame retardance and are improved in impact resistance.
As described above, polycarbonate resins which are excellent in all of flame retardance, impact resistance, fluidity or moldability, and transparency have not yet been obtained.
It is also known that the mechanical strength and heat resistance of polycarbonate resins are increased by compounding glass fibers to the resins. However, compounding the glass fibers to the polycarbonate resins leads to a reduction in fluidity of the resulting composition, and a problem arises in that the moldability of the composition is poor. A polycarbonate resin composition which is intended to improve moldability by using polycarbonate having a specified end group has been proposed (Japanese Patent Application Laid-Open No. 133149/1982).
The above polycarbonate resin composition, however, is not sufficiently satisfactory in respect of moldability because its flow value is as low as 2.32.times.10.sup.-2 ml/sec.